Table_1_Association between olfactory dysfunction and mood disturbances with objective and subjective cognitive deficits in long-COVID.docx

Background and purposeThe coronavirus disease 2019 (COVID-19) has been associated with olfactory dysfunction. The persistent symptoms of anosmia or hyposmia were associated in previous studies with the development of memory impairment and mood disturbances. We aimed to investigate the association between the chronicity of reported olfactory dysfunction and subjective and objective cognitive performance in long-COVID patients and to explore whether their emotional symptoms are related to their cognition.
MethodsOne hundred twenty-eight long-COVID participants were recruited. Reported symptomatology, subjective memory complaints, anxiety and depression symptomatology, and trait-anxiety were assessed. Subjective memory complaints and mood disturbances were compared among groups of participants with olfactory dysfunction as an acute (AOD), persistent (POD), or nonexistent (NOD) symptom. Seventy-six of the volunteers also participated in a face-to-face session to assess their objective performance on tests of general cognitive function and verbal declarative memory. Objective cognitive performance and mood disturbances were compared among the AOD, POD, and NOD groups.
ResultsThe subjective memory complaints and the anxiety and depression symptoms were similar among the groups, but the score in general cognitive function was lower in the participants with symptoms of acute olfactory dysfunction than in those with no olfactory symptoms at any time. Participants’ memory complaints were positively related to their emotional symptoms. The relationship between depressive symptomatology and memory complaints interacted with the olfactory dysfunction, as it only occurred in the participants without symptoms of olfactory dysfunction. Depressive symptomatology and acute olfactory symptoms were negatively associated with general cognitive function and delayed memory performance. The months elapsed from diagnosis to assessment also predicted delayed memory performance. Anxious symptomatology was negatively associated with the immediate ability to recall verbal information in participants who did not present olfactory dysfunction in the acute phase of the infection.
ConclusionOlfactory dysfunction in the acute phase of the infection by COVID-19 is related to cognitive deficits in objective tests, and mood disturbances are associated with self-reported and objective memory. These findings may contribute to further understanding the neuropsychological and emotional aspects of long-COVID.

研究背景与目的
新型冠状病毒肺炎（coronavirus disease 2019，COVID-19）与嗅觉功能障碍密切相关。既往研究表明，持续性嗅觉缺失或嗅觉减退症状与记忆损害及情绪障碍的发生存在关联。本研究旨在探讨长新冠（long-COVID）患者报告的嗅觉功能障碍慢性程度与主观、客观认知表现之间的关联，并探索其情绪症状是否与认知功能相关。

研究方法
本研究共招募128名长新冠患者作为研究对象。对受试者报告的症状、主观记忆主诉、焦虑与抑郁症状以及特质焦虑进行了评估。将受试者按嗅觉功能障碍类型分为急性嗅觉功能障碍（acute olfactory dysfunction, AOD）组、持续性嗅觉功能障碍（persistent olfactory dysfunction, POD）组以及无嗅觉功能障碍（nonexistent olfactory dysfunction, NOD）组，比较三组的主观记忆主诉与情绪障碍情况。其中76名受试者还参与了线下访视，通过通用认知功能与言语陈述性记忆测试评估其客观认知表现，进而比较AOD、POD与NOD三组的客观认知表现与情绪障碍情况。

研究结果
三组受试者的主观记忆主诉、焦虑与抑郁症状水平均无显著差异，但急性嗅觉功能障碍组受试者的通用认知功能评分显著低于全程无嗅觉症状的受试者。受试者的记忆主诉与情绪症状呈正相关。抑郁症状与记忆主诉之间的关联受到嗅觉功能障碍的调节，该关联仅存在于无嗅觉功能障碍的受试者中。抑郁症状与急性嗅觉功能障碍均与通用认知功能及延迟记忆表现呈负相关。从确诊到评估的间隔月数也可预测延迟记忆表现。在感染急性期无嗅觉功能障碍的受试者中，焦虑症状与言语信息即刻回忆能力呈负相关。

研究结论
新型冠状病毒肺炎感染急性期的嗅觉功能障碍与客观测试中的认知缺陷相关，而情绪障碍则与受试者自我报告的记忆情况及客观记忆表现相关。本研究结果有助于进一步阐明长新冠的神经心理与情绪层面特征。